Biomass Cookstoves Research Articles

Household contributions to and impacts from air pollution in India

Airborne fine particulate matter (PM2.5) is the largest environmental risk factor for premature mortality worldwide, and the probable cause of several hundred thousand premature deaths every year in India. Indian households contribute to ambient PM2.5 directly from several sources, including biomass-burning cook stoves and transport, and indirectly through the manufacturing of products triggered by their purchases. Here, we quantify consumption-based PM2.5 contributions from, as well as the mortality burden suffered by, urban and rural households by income deciles. Indirect PM2.5 emissions contribute almost twice as much to ambient PM2.5 concentrations as direct emissions from biomass cook stoves. We find that the impacts are distributed differently from contributions. We show that the mortality risk from indirect sources falls disproportionately on lower-income households. This suggests that industry‐wide pollution controls can reduce inequity in the impacts of ambient air pollution. However, as low-income households face an order of magnitude higher mortality risks from indoor air pollution, clean cooking fuels remain the most effective way to reduce the number of premature deaths from air pollution in India.

Experimental and numerical comparison of CO2 mass flow rate emissions, combustion and thermal performance for a biomass plancha-type cookstove

In this work, the fluid flow, heat transfer, and combustion processes for a plancha-type biomass cookstove are numerically studied. This approach takes into account the numerical solution of mass, momentum, thermal energy, and chemical species conservation equations by using ANSYS Fluent™. Besides the fluid domain, a solid one representing the metallic comal is also considered for the simulations. In particular, numerical results for the CO2 mass flow rate emissions, unburned volatile combustion efficiency (UVE), and thermal efficiency are compared with experimental Water Boiling Tests (WBT) data. For different firepower values, a good comparison is observed. Differences between numerical and experimental results are in the ranges of 2–9% and 1–2% for the CO2 mass flow rates and combustion efficiencies, respectively. Results indicate that the thermal efficiency is higher for the low firepower cases, which is in agreement with experiments.

Direct Improvement in the Combustion Chamber and the Radiant Surface to Reduce the Emission of Particles in Biomass Cooking Stoves Used in Araucanía, Chile

Solid particle emissions from burning wood in three internal combustion biomass cooking stoves commonly used in southern Chile were compared. Each stove was used to show differences in sealing systems, combustion chamber shape, and heating surfaces in order to optimize biomass combustion and the energy produced at a low manufacturing cost. The influence of cooking stove design along with particle and gas emissions that resulted from the biomass combustion within the cooking stove was investigated in this study. Levels of diverse atmospheric contaminants, such as particulate matter, emission factor, NOx, CO2, and CO, and the temperature of the flue gases were determined with the Ch-28 method and UNE-EN 12815. The average emission of particulate matter was significantly reduced by modifying the geometry of the combustion chamber and heating surface of each stove, resulting in 5 g/h particle emissions in conventional equipment and 2 g/h in the improved equipment. In relation to gas emissions, there was a 25% maximum decrease in NOx gases and 35% in CO after modifying the heating surface of each stove. This background supports the evidence of technological improvement with high environmental impact and low economic cost for local manufacturers.

Understanding the current market enablers for Nepal’s biomass cookstove industry

ABSTRACT This paper applies the market map tool to the Nepalese biomass improved cookstove (ICS) sector highlighting existing weaknesses in government policy and biomass cookstove market chains to provide recommendations to better address the social, economic and cultural needs of users. This addresses the problem of low adoption rates of biomass ICS in Nepal. Our research objectives set out to explore the effectiveness of market maps designed for East Africa’s ICS sector (Stevens et al. [2019]. “Market Mapping for Improved Cookstoves: Barriers and Opportunities in East Africa.” Development in Practice.) in Nepal, co-develop a revised market map for Nepal’s biomass ICS sector, conduct a parallel process for institutional-scale biomass ICS and draw on the co-produced market map to inform policy and regulatory frameworks relating to biomass-fuelled ICS. The methodological approach involved reviewing cookstove-related policy documents and regulatory frameworks, undertaking 31 semi-structured interviews, analysing findings from an Institutional Top-Loading Down-Draft (TLUD) Natural Draft Gasifier Pilot study and co-developing the final market map in collaboration with key ICS stakeholders. The results indicate that although government policy actively promotes biomass ICS, this often results in cookstove “stacking” rather than the sustained and exclusive use of clean cooking solutions necessary to promote health benefits. Attention is also focused on the underdeveloped nature of the institutional cookstove market. Our conclusions highlight the usefulness of market maps with a monitoring and evaluation element for identifying barriers to clean cooking uptake and facilitating product improvement by integrating end-user feedback.

Design, Fabrication and Testing of a Forced Draft Biomass Cook Stove

An approach towards an Improvement in performance of cook stoves has been a great challenge to scientists and researchers as biomass cook stoves are one of the basic needs of people living in rural areas. But due to household pollution by Traditional Cook stoves causes illness to people preparing for their regular meals near it. So, taking an initiative for Designing, Fabricating and Improvisation in the performance of Forced Draft cook stoves by placing proper Primary and Secondary holes in combustion chamber which gives better air distribution for proper combustion to get Lower Emission rates. Various experimentations are being performed on the basis of standard protocols i.e. BIS (Bureau of Indian Standards), VITA (Volunteer in Technical Assistance), EPTP (Emission Performance Test Protocol), WBT (Water Boiling Test) amongst which BIS had an upper hand and had very less uncertainty of errors due to which it is mostly being used in checking and improving emission performance of cook stoves for more efficient use with less chances of health issues. This paper consists of Design, Calculations and Constructional working of Forced Draft Biomass Cook stove and also the Burning rate Calculations were carried out to check fuel burnt rate.

Modelling the performance potential of forced and natural-draft biomass cookstoves using a hybrid Entropy-TOPSIS approach

Improved biomass cookstoves have become significantly important as a major technological intervention to aid in the efficient use of biomass fuels. However, the transfer of such technologies to end users do not match the quantity of designs churned out to the market. This study therefore develops a new framework that simultaneously integrates technical, economic, social/public health and environmental factors in assessing the performance potential of biomass cookstoves. Experiments were conducted to determine 13 performance indicators of 20 (forced and natural draft) improved biomass cookstoves and application of the developed methodological framework indicated two main findings: (1) The forced draft cookstoves ranked better with technical and environmental factors while the natural draft cookstoves ranked better with economic and social/public health factors; (2) Considering all four performance indicators simultaneously, the natural draft cookstoves ranked better than the forced draft cookstoves. The results are of significant relevance to governments and organisations for identification of technological designs that should be improved or implemented from a sustainability perspective.

Experimental investigations and thermal analysis of a natural draft improved biomass cookstove with different air conditions

Traditional biomass cookstoves (TCS) are very popular among rural areas and street vendors especially in developing and underdeveloped nations due to their conventional process and simple construction. However, this direct combustion technique is not suitable due to poor efficiency and harmful gaseous-particular emission. Improved biomass cookstoves (ICS) have the potential to overcome the health and environmental problems that are common in the case of TCS. In the present study, investigations were carried out on 3.5 kWth ICS based on gasification design with four different air conditions. The opening to the closing ratio of primary to secondary air vents are taken at 50/50, 50/100, 60/100, and 80/100, respectively for the experiments. Performance of TCS and different ICS cases were compared in terms of burning rate, specific fuel consumption, firepower, useful firepower, thermal efficiency, total particulate matter, and gaseous emissions (CO, CO2, O2, NOx, CC, HC). Apart from that, thermal analysis such as mass balance, energy balance, and exergy efficiency was also calculated. 50/100 opening to the closing ratio of primary to secondary air offers the better performance in terms of higher thermal efficiency and lower gaseous and particulate emission is the major conclusion from this study.

Numerical investigation of the effect of air supply on cook stove performance

Objectives: In a domestic biomass cook stove, the air supply plays a significant role in improving the overall combustion characteristics. The present research aims to numerically investigate the effect of air supply, division of air intake into primary and secondary air, and its optimization. > In a domestic biomass cook stove, the air supply plays a significant role in improving the overall combustion characteristics. The present research aims to numerically investigate the effect of air supply, division of air intake into primary and secondary air, and its optimization. Methods: The geometries of cook stove combustion chamber were prepared and simulated using species transport model with eddy-dissipation turbulent mixing. The stoichiometric amount of air was split into different ratios varying from 50:50 to 10:90 and simulations were carried out for each case. The computational model was validated and the concentration of CO2, H2O, O2, wood volatile and resultant temperature were compared and analyzed. Results: Species transport in the form of conservation of mass along with momentum conservation and energy conservation gave the spatial distribution of resultant species and spatial temperature distribution. The computational domain with feedstock inlet corresponding to the pyrolysis regime has yielded good results compared to that in the front. In this domain, the primary to secondary air ratio of 50:50 showed the best results due to the dominance of primary air utilization and, thus, less secondary air use even at higher elevations. With the maximum temperature near 1300 K, maximum relative CO2 production, and maximum feedstock utilization, the primary to secondary air ratio of 50:50 observed to be optimum. Conclusions: Due to the adequate intermixing of reactant species and uniform diffusion of product species along the combustion chamber's height, the computational domain with feedstock inlet corresponding to the pyrolysis regime has shown realistic conditions. The temperature profile and mole fraction of various species, thus obtained, can be used to design an efficient cook stove as the cross-section and dimensions of the combustion chamber and chimney relates to approach the desired division of air.

Performance and emission characteristics of a micro-gasifier-based cook stove using solid biomass, Melia dubia and Casuarina

Many large-scale improved cooking stove systems have been introduced in various developing countries to replace existing obsolete conventional biomass cooking stoves. Improved cooker stoves exhibit higher performance and lower emissions. In this work, two solid biomass fuels, Melia dubia and Casuarina, were investigated on a dry basis in a forced micro-gasifier stove. The effect of the M. dubia and Casuarina fuels on the thermal efficiency and emission reduction of the forced micro-gasifier stove was analysed using the water boiling test protocol version 4.2.3. The experimental results revealed that the thermal efficiency of the micro-gasifier stove for the fuels M. dubia and Casuarina are 42% and 40%, respectively. The fuel consumption of the micro-gasifier stove was estimated to be 86 g/L for M. dubia and 90 g/L for Casuarina. The carbon monoxide and particulate matter emissions of M. dubia were slightly lower than those of Casuarina. Emissions of carbon monoxide and particulate matter were detected for M. dubia at 22 ppm and 0.05 mg/m3, respectively, and for Casuarina at 25 ppm and 0.07 mg/m3, respectively. The efficiency and emission values for the selected fuels, M. dubia and Casuarina, have shown promising results for the selected micro-gasifier stove.

Impacts of improved biomass cookstoves on child and adult health: Experimental evidence from rural Ethiopia

We present the three-year impacts of an improved biomass cookstove on child and adult health in rural Ethiopia. The Mirt stove is designed to cook injera, the staple bread of Ethiopia estimated to consume 60 percent of household cooking energy and about half of all energy in the country. Though it would not be considered a fully “clean” cooking technology and is not used on a daily basis, Mirt’s documented fuelwood reduction potential and application to the highly energy-intensive baking of injera raises the question of whether it might offer health benefits to users. After near complete stove adoption during an initial one-year randomized controlled trial, 60 percent of treatment households continued to use the improved stoves three-years on and experience moderate reductions in hazardous airborne particulate matter. In a pre-specified analysis, we find treatment status is associated with a precisely estimated 0.3–0.4 standard deviation improvement in height-for-age of young children exposed to the stoves during their first years of life–a substantial effect with implications for greater health and well-being throughout the life course. This association notwithstanding, we find no changes in the respiratory symptoms or physical functioning of older children and adult cooks. Measures of fine particulate matter taken within study households remain over an order of magnitude higher than WHO standards, but follow a statistically significant gradient with respect to the observed height-for-age improvements. The results advance understanding of the health impacts of hazardous air pollution while also refining design and implementation options for interventions geared toward improving well-being in similar environments.

Performance evaluation of two pot raised mud improved cookstove

Biomass cookstove is widely used in the rural areas of Nepal for cooking and space heating. Its thermal and emission performance keeps importance environmentally, economically and socially. Chimney operated two pot raised mud Improved Cookstove (ICS) is one of Nepal’s most promoted cookstoves. The goal of this study is to evaluate the thermal and emission performance. Thermal and emission performance has been obtained by water boiling test and emission parameters have been measured by using Laboratory Emissions Monitoring System (LEMS). The thermal efficiency of cookstove has been improved from 17.99% to 24.7 % i.e. Tier 1 to 2 with the fabrication of appropriate material and accessories. Similarly total emission performance has been found in Tier 1 and fugitive emission performance has been found in Tier 5. Experimental results of thermal efficiency and fugitive emission complied with the performance target of the cookstove.

Does Providing Improved Biomass Cooking Stoves Free-of-Charge Reduce Regular Usage? Do Use Incentives Promote Habits?

Does Providing Improved Biomass Cooking Stoves Free-of-Charge Reduce Regular Usage? Do Use Incentives Promote Habits?

Does Providing Improved Biomass Cooking Stoves Free-of-Charge Reduce Regular Usage? Do Use Incentives Promote Habits?

This article uses a field experiment to evaluate effects of monetary treatments on usage intensity of an important improved biomass-burning cookstove promoted in Ethiopia. Understanding whether, how much and why improved stoves are used are important, because use frequency critically determines fuelwood savings and related benefits. We find that distributing stoves free-ofcharge is at least as effective for promoting short-run adoption as requiring payments or offering usage incentives. Free distribution is most effective at promoting both high and increasing levels of longer-run regular use. First period incentives do not better promote usage habits compared with the other two treatments.

Does Providing Improved Biomass Cooking Stoves Free-of-Charge Reduce Regular Usage? Do Use Incentives Promote Habits?

Does Providing Improved Biomass Cooking Stoves Free-of-Charge Reduce Regular Usage? Do Use Incentives Promote Habits?

Household air pollution related to biomass cook stove emissions and its interaction with improved cookstoves.

IntroductionHousehold air pollution (HAP) is associated with significant global morbidity and mortality. Newer initiatives including improved cookstove (IC) and cleaner fuels are being implemented to improve HAP effects.MethodsA literature review was conducted for household air pollution related to biomass cookstoves in resource limited countries. In January 2018, we electronically searched the PubMed database for the term cookstoves with no date restrictions. We included cohort, case-control, cross-sectional studies, conference abstracts, editorials, and reviews; studies that assessed the emissions related to cookstove and factors affecting HAP emissions.ResultsTwenty-three articles met the objectives of the review. Fine particulate matter with aerodynamic diameter <2.5 µm (PM2.5), carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAH) are the major HAP emissions. Emission factors are based on the stove and fuel used while the activity is based on cooking practices. Changes in composition and sources of PM2.5 causes modification to its resulting toxicity. Many PAHs and their metabolites released by HAP have carcinogenic, teratogenic and mutagenic potential. Improving ventilation decreases concentrations of PM2.5 and CO in the household air. Few standard tools are available to measure ventilation and continued IC efficacy in long term.ConclusionUnavailability of tools to measure ventilation and continued IC efficacy in long term affect uniformity and comparability of IC study results. Community education about the health effects of HAP and importance of ventilation in decreasing HAP is an important aspect of public health policy to prevent HAP effects.

Development of Advanced Biomass Cookstove and Performance Comparisons Using the Modified Star Rating Methodology

A disruptive approach to a fundamental process has been applied in a biomass combustion device with two variable speed fans to supply air for gasification and another for combustion processes, separately. Besides, the preheating of secondary air, required for combustion process was also ensured through annulus chamber before being fed into the combustion chamber. The turbulent flow and homogenous mixing were also ensured by controlling the flow rate resulting in the reduced emissions of carbon monoxide (CO) and fine particulate matter (PM 2.5, particulate matter having aerodynamic diameter

Time Use Implication of Clean Cookstoves in Rural Settings in Ghana: A Time Use Study.

Whilst the health benefit of using clean cookstoves and fuels is widely known, there is limited information on the non-health benefit of these stoves, especially in low-middle-income countries. This paper reports the time use implications of using clean cookstoves and fuels by comparing liquified petroleum gas (LPG), an improved biomass cookstove (BioLite), and traditional biomass cookstoves (three-stone fires) in Ghana. Using survey-based time diaries, information on all the activities undertaken by study participants during a 24-h was collected and analyzed. The findings of the study show that LPG users spent significantly less time gathering firewood compared to the users of improved cookstoves and three-stone fires. LPG users spent slightly less time per cooking episode, generally, and there was no significant difference in cooking time across the three cookstoves mostly due to stove stacking. Time spent engaging in economic activities was highest for LPG users and improved biomass cookstove users, at least when compared to three-stone fire users. In this study, we provide evidence on the time use implications of clean cookstoves, highlighting their non-health benefits and supporting efforts towards the adoption and sustained used of clean cookstoves

Assessing the Respiratory Effects of Air Pollution from Biomass Cookstoves on Pregnant Women in Rural India.

Background: In India, biomass fuel is burned in many homes under inefficient conditions, leading to a complex milieu of particulate matter and environmental toxins known as household air pollution (HAP). Pregnant women are particularly vulnerable as they and their fetus may suffer from adverse consequences of HAP. Fractional exhaled nitric oxide (FeNO) is a noninvasive, underutilized tool that can serve as a surrogate for airway inflammation. We evaluated the prevalence of respiratory illness, using pulmonary questionnaires and FeNO measurements, among pregnant women in rural India who utilize biomass fuel as a source of energy within their home. Methods: We prospectively studied 60 pregnant women in their 1st and 2nd trimester residing in villages near Nagpur, Central India. We measured FeNO levels in parts per billion (ppb), St. George’s Respiratory Questionnaire (SGRQ-C) scores, and the Modified Medical Research Council (mMRC) Dyspnea Scale. We evaluated the difference in the outcome distributions between women using biomass fuels and those using liquefied petroleum gas (LPG) using two-tailed t-tests. Results: Sixty-five subjects (32 in Biomass households; 28 in LPG households; 5 unable to complete) were enrolled in the study. Age, education level, and second-hand smoke exposure were comparable between both groups. FeNO levels were higher in the Biomass vs. LPG group (25.4 ppb vs. 8.6 ppb; p-value = 0.001). There was a difference in mean composite SGRQ-C score (27.1 Biomass vs. 10.8 LPG; p-value < 0.001) including three subtotal scores for Symptoms (47.0 Biomass vs. 20.2 LPG; p-value< 0.001), Activity (36.4 Biomass vs. 16.5 LPG; p-value < 0.001) and Impact (15.9 Biomass vs. 5.2 LPG; p-value < 0.001). The mMRC Dyspnea Scale was higher in the Biomass vs. LPG group as well (2.9 vs. 0.5; p < 0.001). Conclusion: Increased FeNO levels and higher dyspnea scores in biomass-fuel-exposed subjects confirm the adverse respiratory effects of this exposure during pregnancy. More so, FeNO may be a useful, noninvasive biomarker of inflammation that can help better understand the physiologic effects of biomass smoke on pregnant women. In the future, larger studies are needed to characterize the utility of FeNO in a population exposed to HAP.

Effects of a randomized biomass cookstove intervention on glycated hemoglobin among women in Honduras

AIM: Using a stepped-wedge randomized controlled trial, we evaluated impacts of the wood-burning Justa cookstove (engineered combustion chamber, chimney) on glycated hemoglobin (HbA1c) among rural Honduran women. METHODS: We enrolled 230 cooks who were not pregnant, non-smoking, aged 24-59 years, and using a traditional stove. There were 6 study visits per participant, separated by 6 months. Participants were randomized to receive the Justa after 2 visits (Arm 1) or after 4 visits (Arm 2). We measured personal and kitchen 24-hour gravimetric fine particulate matter (PM2.5) and finger-stick HbA1c at each visit. We used linear mixed models adjusted for time and other covariates in intent-to-treat (assigned stove) and exposure-response (estimates per 1-unit higher log-transformed PM2.5) analyses. Sensitivity analyses included: limiting to the first 4 visits to approximate a parallel-trial design and, given large within-person variability in PM2.5 across visits, using geometric mean PM2.5 by assigned stove status for each participant as the exposure-of-interest. RESULTS: Among 227 women with 1,208 observations, Justa stove use reduced median (25th, 75th percentiles) personal PM2.5 concentrations (traditional: 82 µg/m3 [50, 142]; Justa: 43 µg/m3 [27, 73]). Participants had non-significantly reduced HbA1c when using Justa compared to traditional stoves (-0.06%, 95% CI: -0.16, 0.04). No associations were observed between personal and kitchen PM2.5 and HbA1c (0.01%, 95% CI: -0.03, 0.04; 0.02%, 95% CI: -0.01, 0.05; respectively). In sensitivity analyses limited to visits 1-4, a reduction in HbA1c was observed for Justa use compared to traditional stove use (-0.10%, 95% CI: -0.18, -0.01). Geometric mean personal and kitchen PM2.5 exposures were associated with HbA1c (0.03%, 95% CI: -0.03, 0.09; 0.04%, 95% CI: 0.001, 0.08, respectively). CONCLUSIONS: The Justa intervention reduced PM2.5 concentrations, but wide confidence intervals limit interpretations of HbA1c changes in primary analyses. Potentially relevant benefits were observed in sensitivity analyses and will be explored further.

Household Air Pollution Exposure and Childhood Blood Pressure: Evidence from GRAPHS

Background Household air pollution (HAP) exposure results in ~2.8 million premature deaths annually, largely due to cardiovascular disease. The effects of early life HAP exposure, or a clean cookstove intervention, on child blood pressure (BP), are unknown.MethodsThe Ghana Randomized Air Pollution and Heath Study (GRAPHS) randomized pregnant, non-smoking women to one of two cookstove interventions (liquefied petroleum gas, LPG, or improved biomass cookstove) or control, through the index child’s first birthday. Personal HAP exposures [fine particulate matter (PM2.5) and carbon monoxide (CO)] were repeatedly measured prenatally and through child age 4 years. At child age four and five years, we measured resting systolic BP (SBP) and diastolic BP (DBP) (Dinamap Pro 100) per protocol in N=631 children. We employed generalized estimating equations to examine associations between early life CO and PM2.5 and SBP and DBP, following adjustment for maternal age, child sex, BMI, ethnicity and second-hand tobacco smoke exposure. We then employed multivariable linear regression to determine associations between cookstove intervention arm and SBP and DBP. Sex-specific effects were explored.ResultsMedian PM2.5 and CO exposures were 67.5μg/m3 (IQR=42.3-103.6) and 0.87ppm (IQR=0.49-1.41) respectively. Higher early life PM2.5 and CO exposures were independently associated with higher SBP [(PM2.5: 0.24mmHg (0.12-0.35)] per 10μg/m3 increase in PM2.5; CO: 0.59 mmHg (95% CI 0.07-1.12) per 1ppm increase in CO]. Children born to mothers randomized to the LPG arm had lower SBP (-1.62mmHg, 95% CI -3.34, 0.09, p=0.06) and lower DBP (-1.63mmHg, 95% CI -3.13, -0.12, p=0.03), compared to control. Girls were more responsive to the LPG intervention (Girls SBP: -2.73mmHg, 95% CI -5.12, -0.34 vs Boys: SBP: -0.36mmHg, 95% CI -2.85, 2.13).Conclusion Early life HAP exposure is associated with increased SBP in early childhood and a clean-fuel cookstove intervention may ameliorate this effect, particularly amongst girls.